中文说明：可视密码方案实际上是一种秘密共享方案，由Naor和Adi Shamir提出。可视秘密密码方案提供了一种将一个秘密的图像分割成多个子图象的方案，不需要任何密码学的计算就可以通过这些子秘密获得原来的秘密图像。
English Description：
Visual cryptography is actually a secret sharing scheme proposed by Naor and Adi Shamir. Visual secret cryptography provides a scheme to divide a secret image into several sub images. The original secret image can be obtained from these sub secrets without any cryptographic calculation.